Pushing it with two separate questions immediately on signing up but here goes. I'm a hi-fi nut with a very good system. I also use Tidal uncompressed and send it via airplay from Macbook or iPad to a Neet Airstream device that is wired up to my amp. I'm unsure whether this means I'm bypassing the internal computer dac with the Neet device (Wolfson dac) doing the conversion. Considering buying an Arcam airdac to improve sound quality but again don't know if the processing to analogue would still be carried out by the iPad/Macbook internal dac, in which case the Arcam would be pointless. Looking for best sound quality by wireless streaming.

My friend believes AirPlay has quality issues non matter what, and is best avoided. As to your specific question, I was able to find this similar-sounding topic, but using a Marantz receiver rather than your Need device:

AirPlay is a proprietary protocol that uses the Apple Lossless codec (at up to 16/44.1 kHz), encryption, metadata forwarding, and a combination of networking stacks. The audio that the Marantz is receiving is not the native FLAC file, but an ALAC stream, as long as your network is fast enough (throttling may happen under poor network conditions). I'm guessing that the Marantz is seeing the stream as Stereo PCM because AirPlay is embedding that tag in metadata.

So you're always going to be at the mercy of the weakest link in the chain, whether that's Tidal, Apple, your network, Marantz, your cabling, etc.. But the way AirPlay should work in this case is FLAC-to-ALAC ––– lossless all the way!

Sounds like this is not suitable for Tidal's hi-res stream, if that's what you were hoping for:

The hi-res audio streams will typically be 96 kHz/24 bit, according to Tidal, as opposed to the 44.1 kHz/16 bit CD-quality streams on the hi-fi tier. This can be activated by going into the 'Settings" menu, and choosing the "HiFi/Master" quality under “Streaming".

What I'm trying to work out is whether the Tidal stream bypasses the presumably inferior internal dac in the computer and remains in the digital domain until processed by the external dac that has an airplay facility. I assume it must because if the internal computer dac did the conversion it would have to be reconverted to digital to be exported again via airplay. Hope that makes sense. No wonder I stick to conventional hi-fi in the main, streaming and networks are too bloody complicated.